Removal of ammonia from oil shale process waters using a tubular microporous polytetrafluoroethene membrane
Nonosmotic dissolved-gas dialysis (NOGD), a membrane separation process that uses tubular, microporous hydrophobic polytetrafluorethene (PTFE) membranes, was evaluated as an alternative to conventional ammonia removal methods, such as stream stripping. The PTFE membrane serves as a gaseous barrier between two aqueous phases. Dissolved ammonia diffused from the wastewater through the gaseous interface (gas contained in membrane pores) to an acidic absorption solution (dialysate), which served to maintain the concentration gradient of ammonia gas across the membrane wall. A laminar-flow computer model based on this transport process has been developed, and experimental results from treatment of an ammonium hydroxide solution (simulated wastewater) were used to validate its accuracy. This study examined one possible reactor modification, roughening the membrane wall to promote mixing (by disrupting the laminar-flow streamlines near the membrane wastewater interface). The experimental results from a reactor so modified varied extensively; process performance relative to the predicted removals of the laminar-flow model ranged from a decrease of 30% to an increase of 34%. The poor performance of the modified reactor was attributed to operation and maintenance problems associated with membrane fouling. An unsuccessful attempt was made to link the degradation in performance of the modified reactor to water quality parameters: dissolved organic carbon, chemical oxygen demand, polar organic carbon, nonpolar organic nitrogen, dissolved inorganic carbon, or organic Kjeldahl nitrogen concentrations in the oil shale wastewater; none of these characteristics, however, could be identified as the sole contributing factor to poor performance.
- Research Organization:
- California Univ., Berkeley, CA (USA)
- OSTI ID:
- 7032235
- Resource Relation:
- Other Information: Thesis (Ph. D.)
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
AMMONIA
REMOVAL
OIL SHALE PROCESSING PLANTS
WASTE WATER
WATER TREATMENT
AMMONIUM HYDROXIDES
CHEMICAL REACTORS
COMPUTERIZED SIMULATION
DIALYSIS
DIFFUSION
FOULING
LAMINAR FLOW
MATHEMATICAL MODELS
MEMBRANES
MIXING
MODIFICATIONS
OPTIMIZATION
PERFORMANCE TESTING
POLYTETRAFLUOROETHYLENE
POROUS MATERIALS
ROUGHNESS
SEPARATION PROCESSES
WALLS
AMMONIUM COMPOUNDS
FLUID FLOW
FLUORINATED ALIPHATIC HYDROCARBONS
HALOGENATED ALIPHATIC HYDROCARBONS
HYDRIDES
HYDROGEN COMPOUNDS
HYDROXIDES
INDUSTRIAL PLANTS
LIQUID WASTES
MATERIALS
NITROGEN COMPOUNDS
NITROGEN HYDRIDES
ORGANIC COMPOUNDS
ORGANIC FLUORINE COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
ORGANIC POLYMERS
OXYGEN COMPOUNDS
POLYETHYLENES
POLYMERS
POLYOLEFINS
SIMULATION
SURFACE PROPERTIES
TESTING
WASTES
WATER
040900* - Oil Shales & Tar Sands- Waste management